【正文】 道路試驗(yàn) 36/109 滾動(dòng)阻力系數(shù)的影響因素 1. 速度 ua 對(duì) f 的影響 ???????fhkmuconstfhkmuaa/200./100creating a phenomenon of standing wave, heat, shed off, burst. Effect of velocity ua on resistance coefficient f. 脫落和爆裂。 4 430177。 對(duì)其 無(wú)這項(xiàng)要求。 Definition : At the good and straight and even track, the auto driving can reach at the average speed. Main contents: ① Analysis is subjected to the reactions。 eTeTeT PP%PPP???? 1100? 21/109 4～ 6檔變速器 46speed gearbox 6～ 8檔變速器 68speed gearbox 傳動(dòng)軸 drive shaft 離合器 Clutch 主減速器 differential 半軸 semishaft 汽車機(jī)械效率 MV mechanical efficiency ? 轎車 Passenger car ηT=~ ? 商用車 Commercial =~ ? 越野車 (SUV) 4W drive =~ Typical drive system efficiency 22/109 某汽車變速器的機(jī)械效率 Mechanical efficiency of MV gearbox 23/109 輪胎半徑 r Tire radius 自由半徑 r Unloaded radius 靜力半徑 rs Static radius with load 滾動(dòng)半徑 rr Dynamic radius with load rr= rs = r=s/(2πnw) S－ 行駛距離 trip， n－ 轉(zhuǎn)動(dòng)圈數(shù) revolutions 歐洲輪胎與輪輞委員會(huì) (ETRTO)推薦 rr= Fd/(2π) F= radial F= bias 德國(guó)橡膠工業(yè)協(xié)會(huì)推薦 C’R=CR(1+Δua/1000),mm Circumference length 24/109 輪胎半徑 r（ mm) 車型 規(guī)格 自由 靜力 滾動(dòng) 桑塔納 2023 195/60R14 295177。 aur汽車驅(qū)動(dòng)力圖 MV traction force diagram Definition: Use the Ftua curves to describe pletely the MV traction force. If one has already known the full load characteristic curve, transmission , system efficiency and rolling radius, one can calculates the traction forces. tF 26/109 轉(zhuǎn)速－速度 線性變換 gga iirniinrru001602 ?????Tgtqtt riiTrTF ?0??轉(zhuǎn)矩－驅(qū)動(dòng)力 線性變換 )()()(112atqaufnfTnfu??? 27/109 驅(qū)動(dòng)力圖制作 Drawing diagram of traction Ttq Ttq 1 Ttq 2 Ttq 3 Ttq m n n1 n2 n3 … n1m Ft Ft 1 1 Ft 1 2 Ft 1 3 … Ft 1 m ua ua 1 1 ua 1 2 ua 1 3 … ua 1 m I 檔 Ft Ft 2 1 Ft 2 2 Ft 2 3 … Ft 2 m ua ua 2 1 ua 2 2 ua 2 3 … ua 2 m II 檔 Ft Ft 3 1 Ft 3 2 Ft 3 3 … Ft 3 m ua ua 3 1 ua 3 2 ua 3 3 … ua 3 m II 檔 Sp I Sp II Sp III Tgtq ηriiTF 0t = 0= ii rnuga 28/109 1tF 2tF 3tF4tFtF汽車速度汽車驅(qū)動(dòng)力圖Traction MV Velocity MV traction diagram au驅(qū)動(dòng)力 29/109 汽車行駛阻力 滾動(dòng)阻力 Ff :輪胎內(nèi)部摩擦產(chǎn)生的遲滯損失 。常發(fā)生在胎肩與胎側(cè)交界區(qū)。 45/109 1. 前部低 2. 過(guò)渡平滑 3. 后部加擾流板 4. 掠背式 (艙背式 ) 5. 底部導(dǎo)流、平整化，向后應(yīng)逐步升高 6. 整車俯視形狀為腰鼓式 7. 改進(jìn)氣流進(jìn)、出口位置 8. 商用車頂 (側(cè) )部安裝導(dǎo)流罩 46/109 降低汽車空氣阻力的基本思路 Basic thought for decreasing aerodynamic drag MV 47/109 坡道阻力 grade resistance ，＝???????tgshiitgmgFWFii?????????/sinsinsinRoad resistance coefficient ?Grade angle αWF i sin= αWF z cos= 48/109 dtdumsinmg.AuCcosmgfriiTFFFFFaDTgtqjiwft????????????152120汽車行駛方程式 MV motion formula 49/109 dtdummgiAuCmgfriiTaDTgtq ??????20的關(guān)系驅(qū)動(dòng)力和行駛阻力系數(shù) %51cos ????? i??Correlation of drive force and driving resistance ?? FFt 50/109 dtd?dtduau dtdIw?11ZF 1fT1pFdtdum1 1W從動(dòng)輪受力圖 1xF隔離法：平面受力圖 driven tire Insulation method: force diagram with two dimensions Longitudinal force Normal force tangential reaction circumferential force 51/109 grfmrFrdtduIrdtdudtdgrfmTTrFdtdIFFdtdugWFWxwffxwxpZ1111111111111=∴=ω=?=ω==且從動(dòng)輪受力分析 reaction analysis of the moved tire dtdIw?11ZF 1fT1pFdtdum11W1xFVertical force Normal reaction 52/109 gfmdtrduIdtdumFgfmdtrduIFwpwx121111211?????從動(dòng)輪受力分析（續(xù)） dtdIw?11ZF 1fT1pFdtdum11W1xFgrfmrFrdtduIxw 111 ?? gfmdtdurImF wp 12111 )( ???analysis of forces on the moved tire 53/109 au主動(dòng)輪受力圖dtd?dtdudtdIw?22ZF 2fT2pFdtdum2 2W2xFtT?gfmdtdu)rIm(F wp 12 111 ???隔離法：受力圖 Forces reacting on drive tire Insulation method: force diagram with two dimensions 54/109 驅(qū)動(dòng)輪受力分析 222222222fwtxfxtwpxFdtdurIFFTrFTdtdIFFdtdum???????????dtdIw?22ZF 2fT2pFdtdum22W2xF?tTForces acting on the tracition tire 22 WF Z ?除以 r 55/109 ?????????????????dtdurImFFFdtdurIFFdtdumdtdurIFFFwftpwfpwfxt)(222239。 On the hard road, it depends mainly on the category and conditions of road surface, also is relevant with the velocity 路面類型 混凝土（干） 混凝土（濕） 附著系數(shù) ~ ~ 路面類型 碎石 土路（干） 土路（濕） 附著系數(shù) ~ ~ ~ ?? ? ZFF ?? au 68/109 ? 1ZF 2xF1xF dtdum?sinmg ?cosmgmgwF gh ghh ?1fT 2fT1jT 2jTL1L 2L0cossin 21 ?????? ??? mgLmghhdtdumhFTLF ggwwZ0sincos12 ?????? ??? mghmgLhdtdumhFTLF ggwwZaudtdu2ZFL=wheel base B=wheel track 2121 jjff TTTTT ????? 69/109 前輪驅(qū)動(dòng)和后輪驅(qū)動(dòng)時(shí)的地面反力 021 ??????? ?? cosGLsinGhhdtdumTThFLFggjfwwZ對(duì) 后 輪 取 矩 ， 得到 Torque received on rear tire , given Road Reactions on front/rear drive tire !1 ?ZF 70/109 012 ???????? wwggjfwwZ hFsinGhhdtdumTThFcosGLLF ??對(duì)前輪取矩，得到 Torque received on front tire,